THE FRAGMENT-R COLLISION - WM-KEEK-TELESCOPE OBSERVATIONS OF SL9

The W. M. Keck telescope was used to observe the impact of comet Shoem aker-Levy 9 (SL9) fragment R at a wavelength of 2.3 micrometers on 21 July 1994. The data showed three outbursts. The first flash lasted abo ut 40 seconds and was followed 1 minute after its peak by a second fla sh that lasted about 3 minutes. A third, longer lasting flare began 6 minutes after the first flash and lasted for 10 minutes. At its maximu m brightness, the flare outshone Jupiter. The two short flashes are pr obably associated with the initial meteor trail and the subsequent fir eball, respectively. The bright flare occurred when the impact site ro tated into view. These data show that the explosion ejected material a t least 1300 kilometers above the visible cloud tops. The luminosity o f the impact site during the long bright flare was probably maintained by the release of gravitational potential energy, as this material fe ll back onto the lower atmosphere.